1. Field of the Invention
The present invention relates to a data transfer method, data transfer program, storage medium and terminal, by which data received from a server can be rewritten at a high efficiency in a short period of time.
2. Description of the Related Art
Recent years, services that transmit a great amount of image information and sound information at a high speed through the Internet are becoming more popular. One of the examples of the services is a digital communication network called broadband. The broadband is very useful, but it entails some drawbacks such as the service fee being still very high and having to prepare expensive device and software application.
Meanwhile, document modification information such as the size of characters and a layout, information indicating the attribution of data, and the like are directly embedded in a text using a markup language such as HTML, and they are transmitted or received with the text. It is well known that when embedding information, a location where an image file is displayed, and a link can be specified. Further, a page containing a still image, moving image, sound and the like can be also expressed, and such pages stored in a WWW server on the Internet are frequently transmitted and received to be browsed with use of a WWW browser. Transmission of the data that express a page is carried out usually in units of data corresponding to one display image (1 frame).
Further, in order to update the data that expresses a page, or to obtain the corresponding data by accessing, for example, a sound information resource such as for music, that relates to the image displayed on the page, all the data that correspond to a respective page are updated as one object, and therefore new data are transmitted and received. In the case where a display on the screen of a local computer is partially updated, the data corresponding to the entire display image (1 whole frame) that contains the portion to be updated, are transmitted and received between the local computer and a remote computer (server). In the above-described conventional technique, even if data to be updated or to be newly obtained is merely a part of the data corresponding to one entire display image (1 whole frame), the data of that entire display image (1 whole frame) are transmitted and received in any case. In this manner, a great amount of data that contains data items that correspond to a portion need not be changed, which therefore need not be transmitted or received, is transferred anyway, and thus its transmission line is occupied wastefully. Further, it takes a considerable amount of time to be prepared for the transmission and reception of the data.
In extreme cases, while browsing data on the Internet with use of the WWW browser, for example, each time some kind of an event is created with regard to one display image (1 frame) of a terminal by pressing on a key, moving of the mouse, clicking on an operation button or the like, the transmission and reception of all the data of the image always occur. As a result, the efficiency for transmission and reception of necessary data becomes poor and in many cases, the response property is not satisfactory for the users.